Magnesium base alloy



Patented July 265-1938 I UNITED STATES PATENT OFFICE MAGNESIUM BASE' ALLOY John A. Gann, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich.) a corporation 01' Michigan g s No Drawing. Application May 29, 1937, Serial 3 Claims. (01. 75--168) s This invention relates to magnesium alloys and pa-risons are made on heat treated and heat more specifically to those containing a minor pertreated andaged alloys..

c n f mercury. Pr erties cast allo The object of the invention is the production oi 0p I vs a magnesium alloys with improved physical proper- 5 ties and. the production of alloys that are amen- Composition 12E23, 23g my able to heat treatment. Other objects and ad- 'l -l 11L 11888 vantages will appear as the description proceeds.

My invention is based on the discovery that Mg+%Al 21,600 12,700 51.8

m highly desirable and useful alloys can be prepared ggiififiig %"8 g gj'g g 10 by alloying mercury with magnesium alloys and v that such alloys possess good strength characteristics and that these strength characteristics can Properties of heat treated allows be further improved by heat treatment.

1 have discovered that the properties of binary giiggtfgjjjjjjjjjj thigh, 100 -1238; 3, 33 15 magnesium-mercury alloys may be improved by s+ z--- 0, 13,20015,000 Hall the addition of aluminum and that the properties o t e binary a e u u m alloys may Properties of heat treated and aged alloys be improved by the addition of mercury or, in i other words, that the resultant ternary magne- Mg+m%Al 26,400 17,500 6&0 20 slum-aluminum-mercury alloy has physical prop- Mg+18%Hg r- 13,200-22,400 2,900- 3,500 30. 9-35.!) erties which are superior to those of either parent Mg+1%A1+1"8%Hg"" binary alloy. I have discovered that this beneflcial result is obtained in alloys containingfrom s Property Improvements are hkewlse about to 15 per cent f aluminum a f m tamed in alloys containing relatively low per- 5 about 0.5 to 10 per cent of mercury, the balance centages of aluminum- ?hese alloys) are being substantially magnesium where castings entiated from those described above in that they are to be prepared requiring maximum yie are not amenable to heat treatment but do lend strength and hardness, I normally pref r alloys themselves to fabrication by plastic deformation containing 8 to 12 per cent of aluminum and 2 to Processes- 8 per cent of mercury. Where toughness is re- The beneficial results Obtamed by the simulquired, or if plastic-deformation is essential, the taneous Presence 0f aluminum and mercury in alloy Should preferably contain 2 to 3 per cent cast alloys containing a low percentage of aluof aluminum and 5 to 4 per cent of mercury. minum are illustrated by the following data.

5 The properties of these magnesium-mercuryproperties of cast alloys 35 aluminum alloys are retained, in general, and in many instances may be improved when the alloy Tensile Yield Elongw Brine likewise contains other alloying ingredients. For Composition strength, strength, tion, hardmost purposes, the alloy should normally contain perm" more than 80 per cent of magnesium and less 40 than 20 per cent of total added metals. 1 s+ 21100 3 Examples of the property improvements obfifistiii f' MM 30033'0 tained in these new ternary magnesium-alumi- B----- ammo-30,100 6300-81300 9418-40-5 num-mercury alloys in the as cast condition, as compared to the parent binary alloys are given hese ter a y a u ume c y 45 in the accompanying tables. It will be noted that lloys may be p ep by the Well known meththe magnesium-aluminum-mercury alloys are suods of alloying metals with magnesium, such as prior to both the binary magnesium-aluminum by adding the respective-alloying ingredients to and binary magnesiu'm mercury alloys from the a bath of molten metalprotected from oxidation standpoint of various physical characteristics, by a cover of afluid flux. In general, however, it 50 specifically tensile strength, yield strength, and is preferable to add the mercury as ,a magnesiumpercentage elongation. It should likewise be mercury amalgam prepared by digesting mercury noted that the magnesium-aluminum-mercury with magnesium shavings at or near room temalloys are superior to the magnesium-aluminum perature. Castings may be prepared by die castand the magnesium-mercury alloys when coming or the like, or by sand casting in molding sand 55 treated with an oxidation inhibitor, sucl'! as sulfur or ammonium fluoride. Heat treatment may be carried out by heating the alloy for about 18 hours at 75077 5 F. Aging may consist of a subsequent heating for 16-18 hours at approximately 350 F. Plastic deformation operations are best conducted in the temperature range of GOO-750 F. Other modes of applying the principle 01' my invention may be employed instead of those explained, change being made as regards the ingre- ,dients herein disclosed, provided those stated by any of the following claims or their equivalent be employed. V

I particularly point out and distinctly claim as about 0.5 to 10 per cent of mercury, the balance being magnesium.

2. A magnesium-base alloy containing from about 8 to 12 per cent of aluminum and from about 2 to =8 per cent of mercury, the balance being magnesium.

3. A magnesium-base alloy containing from about 2 to 8 per cent of aluminum and 0.5 to 4 per cent of mercury, the balance being magne- 

